At the start of Westerson’s so-so 11th whodunit featuring investigator Crispin Guest (after 2017’s Season of Blood), set in 1392 London, Guest agrees to help Fr. Bulthius Braydon with a strange case. Braydon claims to have witnessed corpses walking one night in the cemetery adjacent to his church, St. Modwen’s. The priest’s fears of supernatural evil only increased when, on the following day, he found opened coffins whose occupants had blood on their mouths. Meanwhile, Guest takes on a mystery with a personal angle after he hears from Philippa Walcote, “who had broken his heart by marrying another.” Philippa’s seven-year-old son, Christopher, who bears an uncanny resemblance to Guest, was found next to the corpse of their neighbor and is suspected of stabbing him to death after the victim supposedly caught the boy trying to steal a relic. The clichéd second case lessens the impact of the first, more unusual one. Fans of 14th-century mysteries set in England will be better served by Susannah Gregory’s Matthew Bartholomew series. (Aug.)